swiotlb: fix wrong panic

fba99fa3 · FUJITA Tomonori <[email protected]> · 2011-02-25 14:44:16 -08:00

swiotlb's map_page wrongly calls panic() when it can't find a buffer fit
for device's dma mask.  It should return an error instead.

Devices with an odd dma mask (i.e.  under 4G) like b44 network card hit
this bug (the system crashes):

   http://marc.info/?l=linux-kernel&m=129648943830106&w=2

If swiotlb returns an error, b44 driver can use the own bouncing
mechanism.

Reported-by: Chuck Ebbert <[email protected]>
Signed-off-by: FUJITA Tomonori <[email protected]>
Tested-by: Arkadiusz Miskiewicz <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: fba99fa38b023224680308a482e12a0eca87e4e1
Parents: f8407f26

Changes

1 files changed · +4 −2

File	Status	Add	Del	Content
lib/swiotlb.c	modified	+4	−2	View file

lib/swiotlb.c

View file

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index c47bbe1..93ca08b 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -686,8 +686,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 	/*
 	 * Ensure that the address returned is DMA'ble
 	 */
-	if (!dma_capable(dev, dev_addr, size))
-		panic("map_single: bounce buffer is not DMA'ble");
+	if (!dma_capable(dev, dev_addr, size)) {
+		swiotlb_tbl_unmap_single(dev, map, size, dir);
+		dev_addr = swiotlb_virt_to_bus(dev, io_tlb_overflow_buffer);
+	}
 
 	return dev_addr;
 }